Abstract: A combustion apparatus and a combustion system for an internal combustion engine wherein a funnel-shaped cone with an orifice at the apex thereof is provided in a combustion chamber and spaced from an ignition apparatus so that as a gaseous, combustible mixture is introduced into the chamber, it flows through the cone to the orifice where it is ignited by the ignition apparatus so that the flame caused thereby explodes outwardly through ejection openings and along the external surface of the cone into the chamber so as to envelope the uncombusted gases and cause maximum explosion and combustion of the mixture automatically. The structure is applicable to existing conventional spark ignition engines when the cone is provided at the front end portion of the spark plug. For compression ignition engines, the cone is provided in a pre-combustion chamber in the cylinder head or is attached to the cylinder head and extends into a chamber provided in the piston.